NiS2@NiOOH/CNT hybrid as robust catalyst for oxygen evolution reaction

Development of non-precious metal-based oxygen evolution reaction (OER) catalysts is essential for commercial scale electrochemical water splitting. In this paper, a carbon nanotube (CNT), which can enhance the conductivity of the catalyst, supported nickel sulfide (NiS 2 ) and nickel oxyhydroxide (NiOOH) hybrid (NiS 2 @NiOOH/CNT) based catalyst is prepared. The in-situ conversion of partial NiS 2 to NiOOH not only increased the active catalytic sites but also decreased the OER overpotential to 195 mV at the current intensity of 10 mA/cm 2 . The long-time running stability test results showed that the current density almost no losses detected after 10 h continuous operation at a fixed potential of 1.61 V (vs. RHE) in 1 M KOH. The density functional theory (DFT) calculations proved that the NiS 2 @NiOOH/CNT catalyzed OER follows the lattice‑oxygen-mediated (LOM) mechanism, which illustrated the mechanism for the high catalytic performance for OER. This paper provides a novel way to design high performance electrocatalysts for OER from nickel based materials.